High nitrile resins containing maleic anhydride

ABSTRACT

Polymeric compositions having high softening temperatures, good gas barrier properties and low creep properties are composed of an olefinically unsaturated nitrile, another monovinyl component and maleic anhydride and optionally a diene monomer.

This is a continuation of application Ser. No. 027,956 filed Apr. 9,1979, now abandoned which is a continuation of application Ser. No.944,109, filed Sept. 20, 1978, now U.S. Pat. No. 4,197,263 which in turnis a continuation of patent application Ser. No. 806,577, filed on June15, 1977, now abandoned.

This invention relates to novel polymeric compositions which have highheat-distortion temperatures, good gas barrier properties and low creepcharacteristics which are composed of an olefinically unsaturatednitrile, another monovinyl component and maleic anhydride and optionallya conjugated diene monomer, and to the process for manufacture of thesecompositions.

The novel polymeric products of this invention are prepared bypolymerizing a major portion of an olefinically unsaturated nitrile,such as acrylonitrile, and a minor portion of another monovinyl monomercomponent which must include maleic anhydride optionally in the presenceof a preformed rubbery polymer composed of a conjugated diene monomer,such as butadiene.

The conjugated dienes useful in this invention include butadiene-1,3,isoprene, chloroprene, bromoprene, cyanoprene, 2,3-dimethyl butadiene,and the like. Most preferred for the purpose of this invention arebutadiene and isoprene because of their ready availability and theirexcellent copolymerization properties.

The olefinically unsaturated nitriles useful in this invention are thealpha,beta-olefinically unsaturated mononitriles having the structure##STR1## wherein R is hydrogen, a lower alkyl group having from 1 to 4carbon atoms, or a halogen. Such compunds include acrylonitrile,alpha-chloroacrylonitrile, alpha-fluoroacrylonitrile, methacrylonitrile,ethacrylonitrile, and the like. The most preferred olefinicallyunsaturated nitrile is acrylonitrile.

The other monovinyl monomer component copolymerizable with theolefinically unsaturated nitriles which are useful in this inventionincludes one or more of the vinyl aromatic monomers, esters ofolefinically unsaturated carboxylic acids, vinyl esters, vinyl ethers,alpha-olefins, and others.

The vinyl aromatic monomers include styrene, alpha-methyl styrene, thevinyl toluenes, the vinyl xylenes, and the like. Most preferred arestyrene and alpha-methyl styrene.

The esters of olefinically unsaturated carboxylic acids include thosehaving the structure ##STR2## wherein R₁ is hydrogen, an alkyl grouphaving from 1 to 4 carbon atoms, or a halogen, and R₂ is an alkyl grouphaving from 1 to 6 carbon atoms. Compounds of this type include methylacrylate, ethyl acrylate, the propyl acrylates, the butyl acrylates, theamyl acrylates, and the hexyl acrylates; methyl methacrylate, ethylmethacrylate, the propyl methacrylates; the butyl methacrylates, theamyl methacrylates, and the hexyl methacrylates; methylalpha-chloroacrylate, ethyl alphachloroacrylate, and the like. Mostpreferred in the present invention are methyl acrylate, ethyl acrylate,methyl methacrylate, and ethyl methacrylate.

The alpha-olefins useful in the present invention are those having atleast 4 and as many as 10 carbon atoms and having the structure ##STR3##wherein R' and R" are alkyl groups having from 1 to 7 carbon atoms, andmore specifically preferred are alpha-olefins such as isobutylene,2-methyl butene-1, 2-methyl pentene-1, 2-methyl hexene-1, 2-methylheptene-1, 2-methyl octene-1, 2-ethyl butene-1, 2-propyl pentene-1, andthe like. Most preferred is isobutylene.

The vinyl ethers include methyl vinyl ether, ethyl vinyl ether, thepropyl vinyl ethers, the butyl vinyl ethers, methyl isopropenyl ether,ethyl isopropenyl ether, and the like. Most preferred are methyl vinylether, ethyl vinyl ether, the propyl vinyl ethers, and the butyl vinylethers.

The vinyl esters include vinyl acetate, vinyl propionate, the vinylbutyrates, and the like. Most preferred is vinyl acetate.

Maleic anhydride is an essential component of the novel compositionsembodied in this invention.

The polymeric compositions of the present invention can be prepared byany of the known general techniques of polymerization, including thebulk polymerization, solution polymerization, and emulsion or suspensionpolymerization techniques by batch, continuous or intermittent additionof the monomers and other components. The preferred method is bysolution polymerization in the presence of a suitable solvent and afree-radical generating polymerization initiator at a temperature in therange of from about 0° to 100° C. in the substantial absence ofmolecular oxygen.

The rubbery polymers which may be included in the resins of thisinvention are homopolymers of the conjugated diene monomers mentionedabove as well as copolymers of these dienes and another monomercomponent such as acrylonitrile, styrene, ethyl acrylate, and mixturesthereof, wherein there is present at least 50% by weight of the totalmonomers of the conjugated diene monomer.

The preferred polymeric compositions embodied herein are those resultingfrom the polymerization of 100 parts by weight of (A) at least 50% byweight of at least one nitrile having the structure ##STR4## wherein Rhas the foregoing designation, (B) from 1 to 30% by weight of maleicanhydride, and (C) from 5 to 25% by weight based on the combined weightof (A) plus (B) plus (C) of at least one member selected from the groupconsisting of (1) styrene or alpha-methyl styrene, (2) an ester havingthe structure ##STR5## wherein R₁ and R₂ have the foregoingdesignations, (3) an alpha-olefin having the structure ##STR6## whereinR' and R" have the foregoing designations, (4) a vinyl ether selectedfrom the group consisting of methyl vinyl ether, ethyl vinyl ether, thepropyl vinyl ethers, and the butyl vinyl ethers, and (5) vinyl acetate,in the presence of from 0 to 40 parts by weight of (D) a rubbery polymerof a conjugated diene monomer selected from the group consisting ofbutadiene and isoprene and optionally at least one comonomer selectedfrom the group consisting of styrene, a nitrile monomer having thestructure ##STR7## wherein R has the foregoing designation, and an esterhaving the structure ##STR8## wherein R₁ and R₂ have the foregoingdesignations, said rubbery polymer containing from 50 to 100% by weightof polymerized conjugated diene and from 0 to 50% by weight ofcomonomer. Preferably, component (A) should be present in from about 60to 90% by weight, component (B) should be present in from 1 to 30% byweight and component (C) should be present in from 5 to 25% by weightbased on the combined weight of (A) plus (B) plus (C).

The novel polymers produced by the process of this invention are readilyprocessed thermoplastic materials which can be thermoformed into a widevariety of useful articles in any of the conventional ways employed withknown thermoplastics materials, such as by extrusion, milling, molding,drawing, injecting, etc. The polymeric products of this invention haveexcellent solvent resistance and their impact strength and lowpermeability to gases and vapors make them useful in the packagingindustry, and they are particularly useful in the manufacture ofbottles, film, sheet, pipes and other types of containers for liquidsand solids.

In the following illustrative examples, the amounts of ingredients areexpressed in parts by weight unless otherwise indicated.

EXAMPLE 1

A. An acrylonitrile-styrene copolymer which is outside the scope of thepresent invention was prepared in a polymerization reactor to which wereadded 75 parts of acrylonitrile, 3 parts of styrene and 75 parts ofmethyl ethyl ketone. The mixture was stirred and brought to 76° C. underan atmosphere of nitrogen. A feed of 22 parts of styrene, 25 parts ofmethyl ethyl ketone and 0.3 part of azobisisobutyronitrile was addedcontinuously and uniformly over a 4.5-hour period. The final reactionmixture was maintained at 76°-78° C. for an additional hour. The overallconversion of monomers to polymer was 68% of theory.

The contents of the reactor were poured into a stirred mixture of 1:1 byvolume benzene:petroleum ether. The solid polymer was isolated and driedat reduced pressure and 45°-60° C. for 48 hours. This resin was found tohave an ASTM heat-distortion temperature of 84°-94° C., a flexuralstrength of 17.1×10³ psi, a flexural modulus of 5.50×10⁵ psi, a tensilestrength of 14.1×10³ psi, an oxygen transmission rate of 3.5 cc-mil/100inches² /24 hours/atmosphere and a water vapor transmission rate of 8.0gm/mil/100 inches² /24 hours/atmosphere.

B. An acrylonitrile-styrene-maleic anhydride terpolymer which is withinthe scope of the present invention was prepared by the procedure of A ofthis Example except that the continuous feed was made up of 5 parts ofmaleic anhydride, 17 parts of styrene, 25 parts of methyl ethyl ketoneand 0.3 part of azobisisobutyronitrile and the continuous feed was addeduniformly over a 5-hour period. The overall conversion of monomers topolymer was 80% of theory. The resin thus produced was found to have anASTM heat-distortion temperature of 102° C., a flexural strength of18.7×10³ psi, a flexural modulus of 6.06×10⁵ psi, a tensile strength of15.2×10³ psi, an oxygen transmission rate of 4.6 cc-mil/100 inches² /24hours/atmosphere and a water vapor transmission rate of 0.9 gm-mil/100inches² /24 hours/atmosphere.

EXAMPLE 2

The procedure of Example 1A was followed except that the initial reactorcharge was 70 parts of acrylonitrile, 2.8 parts of styrene, 75 parts ofmethyl ethyl ketone and the continuous feed was made up of 5 parts ofmaleic anhydride, 22.2 parts of styrene, 25 parts of methyl ethyl ketoneand 0.3 part of azobisisobutyronitrile. The continuous feed was addeduniformly over a 6-hour period. The overall conversion of monomers topolymer was 81% of theory. The resulting resinous polymer was found tohave an ASTM heat-distortion temperature of 104° C., a flexural strengthof 18.9×10³ psi, a flexural modulus of 6.13×10⁵ psi and a tensilestrength of 14.2×10³ psi.

EXAMPLE 3

A polymer was prepared by the procedure described in Example 2 using aninitial reactor charge of 70 parts of acrylonitrile, 2.8 parts ofstyrene and 75 parts of methyl ethyl ketone and a continuous feed madeup of 10 parts of maleic anhydride, 17.8 parts of styrene, 25 parts ofmethyl ethyl ketone and 0.3 parts of azobisisobutyronitrile. Theresulting resin was found to have an ASTM heat-distortion temperature of107° C., a flexural modulus of 6.03×10⁵ psi, an oxygen transmission rateof 2.7 cc-mil/100 inches² /24 hours/atmosphere and a water vaportransmission rate of 5.4 gm-mil/100 inches² /24 hours/atmosphere.

EXAMPLE 4

A. A copolymer of acrylonitrile and methyl acrylate which is outside thescope of this invention was prepared by adding to a polymerizationreactor 75 parts of acrylonitrile, 25 parts of methyl acrylate, 100parts of methyl ethyl ketone and 0.1 part of azobisisobutyronitrile. Thepolymerization reaction was carried out for 2 hours at 77° C. withstirring under a nitrogen atmosphere. The polymer was isolated bycoagulation with a 1:1 by volume mixture of benzene:petroleum ether. Thedried resinous polymer was found to have an ASTM heat-distortiontemperature of 76° C., a flexural strength of 21.4×10³ psi, a flexuralmodulus of 6.56×10⁵ psi, a tensile strength of 10.6×10³ psi, an oxygentransmission rate of 0.35 cc-mil/100 inches² /24 hours/atmosphere and awater vapor transmission rate of 4.3 gm-mil/100 inches² /24hours/atmosphere.

B. The procedure of A of this Example was followed except that theingredients of the polymerization mixture were 70 parts ofacrylonitrile, 20 parts of methyl acrylate, 10 parts of maleicanhydride, 100 parts of methyl ethyl ketone and 0.1 part ofazobisisobutyronitrile. The resulting polymer was found to have an ASTMheat-distortion temperature of 83° C., a flexural strength of 25.5×10³psi, a flexural modulus of 0.75×10⁵ psi, a tensile strength of 13.4×10³psi, an oxygen transmission rate of 0.24 cc-mil/100 inches² /24hours/atmosphere and a water vapor transmission rate of 3.2 gm-mil/100inches² /24 hours/atmosphere.

EXAMPLE 5

The procedure of Example 4A was repeated except that the ingredients ofthe polymerization mixture were 60 parts of acrylonitrile, 20 parts ofmethyl acrylate, 20 parts of maleic anhydride, 100 parts of methyl ethylketone and 0.1 part of azobisisobutyronitrile. The resulting polymer wasfound to have an ASTM heat-distortion temperature of 79° C., a flexuralstrength of 21.7×10³ psi, a flexural modulus of 6.49×10⁵ psi and atensile strength of 16.2×10³ psi.

We claim:
 1. The polymeric composition resulting from the polymerizationof 100 parts by weight of(A) from 60 to 90% by weight of at least onenitrile having the structure ##STR9## wherein R is hydrogen, a loweralkyl group having from 1 to 4 carbon atoms, or a halogen, (B) from 1 to30% by weight of maleic anhydride, and (C) from 5 to 25% by weight of atleast one member selected from the group consisting of(1) an esterhaving the structure ##STR10## wherein R₁ is hydrogen, an alkyl grouphaving from 1 to 4 carbon atoms, or a halogen, and R₂ is an alkyl grouphaving from 1 to 6 carbon atoms, (2) a vinyl ether selected from thegroup consisting of methyl vinyl ether, ethyl vinyl ether, the propylvinyl ethers, and the butyl vinyl ethers, and (3) vinyl acetate,whereinthe weight percentages of (A), (B) and (C) are based on the combinedweight of (A) plus (B) plus (C).
 2. The composition of claim 1 wherein(A) is acrylonitrile.
 3. The composition of claim 2 wherein (C) ismethyl acrylate.
 4. The process comprising polymerizing in the presenceof a solvent, a free-radical initiator and in the substantial absence ofmolecular oxygen 100 parts by weight of(A) from 60 to 90% by weight ofat least one nitrile having the structure ##STR11## wherein R ishydrogen, a lower alkyl group having from 1 to 4 carbon atoms, or ahalogen, (B) from 1 to 30% by weight of maleic anhydride, and (C) from 5to 25% by weight of at least one member selected from the groupconsisting of(1) an ester having the structure ##STR12## wherein R₁ ishydrogen, an alkyl group having from 1 to 4 carbon atoms, or a halogen,and R₂ is an alkyl group having from 1 to 6 carbon atoms, (2) a vinylether selected from the group consisting of methyl vinyl ether, ethylvinyl ether, the propyl vinyl ethers, and the butyl vinyl ethers, and(3) vinyl acetate,wherein the weight percentages of (A), (B) and (C) arebased on the combined weight of (A) plus (B) plus (C).
 5. The process ofclaim 4 wherein (A) is acrylonitrile.
 6. The process of claim 4 wherein(C) is methyl acrylate.
 7. The composition of claim 1 which results inthe polymerization of 5 to 30% by weight of maleic anhydride.
 8. Thecomposition of claim 1 which results from the polymerization of 5 to 20%by weight of maleic anhydride.
 9. The composition of claim 1 whichresults from the polymerization of 70 to 75% by weight of (A).
 10. Theprocess of claim 6 wherein (B) is 5 to 30% by weight.
 11. The process ofclaim 6 wherein (B) is 5 to 20%.
 12. The process of claim 6 wherein (A)is 70 to 75%.
 13. The polymeric composition which consists essentiallyof polymerizing 100 parts by weight of(A) from 60 to 90% by weight of atleast one nitrile having the structure ##STR13## wherein R is hydrogen,a lower alkyl group having from 1 to 4 carbon atoms, or a halogen, (B)from 1 to 30% by weight of maleic anhydride, and (C) from 5 to 25% byweight of at least one member selected from the group consisting of(1)an ester having the structure ##STR14## wherein R₁ is hydrogen, an alkylgroup having from 1 to 4 carbon atoms, or a halogen, and R₂ is an alkylgroup having from 1 to 6 carbon atoms, (2) a vinyl ether selected fromthe group consisting of methyl vinyl ether, ethyl vinyl ether, thepropyl vinyl ethers, and the butyl vinyl ethers, and (3) vinylacetate,wherein the weight percentages of (A), (B) and (C) are based onthe combined weight of (A) plus (B) plus (C).